基于γ宽束衰减的方位密度测井间隙计算及应用  

Standoff calculation and application of azimuthal density logging based on broadbeamγ-ray attenuation

作　　者：于华伟[1,2] 张倩文 王哲[1,2] 罗琳 刘睿 于其蛟[4] 杜海洋 韩春田 YU Huawei;ZHANG Qianwen;WANG Zhe;LUO Lin;LIU Rui;YU Qijiao;DU Haiyang;HAN Chuntian(National Key Laboratory of Deep Oil and Gas,China University of Petroleum(East China),Qingdao 266580,China;School of Geosciences,China University of Petroleum(East China),Qingdao 266580,China;Archives,China University of Petroleum(East China),Qingdao 266580,China;MWD/LWD&Logging Research Institute,Sinopec Matrix Corporation,Qingdao 266075,China)

机构地区：[1]深层油气全国重点实验室(中国石油大学(华东)),青岛266580 [2]中国石油大学(华东)地球科学与技术学院,青岛266580 [3]中国石油大学(华东)档案馆,青岛266580 [4]中石化经纬地质测控技术有限公司,青岛266075

出　　处：《核技术》2023年第11期64-72,共9页Nuclear Techniques

基　　金：山东省自然科学基金(No.ZR2022MD019);中国石油天然气集团有限公司科学研究与技术开发项目(No.2021DJ3801);中央高校基本科研业务费(No.22CX01001A-2);中国石油大学(华东)探究性实验项目资助。

摘　　要：随钻测井中准确计算仪器与井壁的间隙及井眼尺寸是进行井眼环境校正、提高测量精度的前提。为了研究间隙的精确计算方法,首先基于γ射线宽束衰减模型,针对随钻方位密度的测井响应推导了间隙尺寸的理论计算公式;随后将仪器的蒙特卡罗数值模拟结果与实验数据基准对比检测,并模拟研究间隙、泥浆密度、地层密度等因素对探测器响应的影响,得到精确的间隙计算公式;最后利用模拟和实测数据,验证了间隙计算方法的准确性。结果表明:模拟数据计算的间隙结果与理论值基本一致,实测数据处理的间隙与超声间隙吻合较好,且所计算井径也和电缆井径有良好的对应关系,即使在小间隙、超声间隙存在异常时仍能提供精准测量。密度间隙计算的适用范围为0~3.81 cm,可以与更大量程的超声测量相互补充,从而为随钻测井仪器的井眼校正提供关键参数。[Background]Accurately calculating the borehole size and standoff between the tool and borehole wall is the premise for correcting the effect of the borehole environment and improving measurement precision in logging while drilling(LWD).[Purpose]This study aims to obtain an accurate calculation method for the standoff size of LWD.[Methods]Firstly,the theoretical relationship of the standoff was derived based on the broad-beamγ-ray attenuation model for azimuth density LWD.Then,Monte Carlo N-Particle transport code(MCNP)was employed for simulation,and results were benchmarked according to experimental tool data.By analyzing the influence of standoff,mud and formation density,and other factors on the detector response,an accurate standoff calculation formula was derived.Finally,logging curves were drawn using the CIFLog platform and the calculated standoff results were compared with the measured ultrasonic results,hence to verify the accuracy of the proposed standoff calculation method.[Results]The calculated standoff results in the simulation are fundamentally consistent with the theoretical value.The calculation result using measured data processing is in approximate agreement with the ultrasonic standoff,and the calculated calipers have good correspondence with the wireline well diameter.The proposed method provides accurate measurement even when the standoff is small and ultrasonic standoff measurement is abnormal.The applicable range of standoff calculation based on azimuthal density LWD is 0~3.81 cm.[Conclusions]The broad-beamγ-ray attenuation based standoff calculation method for density LWD complements to larger range ultrasonic measurements to provide key parameters for borehole correction for LWD tools.

关 键 词：随钻方位密度测井 宽束衰减 间隙 井径 蒙特卡罗模拟 

分 类 号：TL99[核科学技术—核技术及应用] P631.817[天文地球—地质矿产勘探]